Regulators with Flow Adjustable Knobs

[Bob DBF]

My favorite reg is the one I am breathing on

I'm glad to hear we like the same regs.

One of my major concerns with regs is that they give me air, I'm not as particular as some at how much work it takes to suck it out. That being said, I find that well tuned unbalanced seconds give me plenty of air easily regardless of depth. The balanced and venturi seconds are noticibly better, assuming proper tuning, but not enough for me to pull out the wallet for them. I do have a couple of balanced seconds but I don't go out of my way to always use them, the balanced 109 is used for my backup.

I got used to breathing regs in the '60's and getting all the air I needed for the deep dives we were doing at the time, and they work the same now.

The way I look at it, is that divers that are used to getting all the air they possibly want are at a disadvantage if they have to use a harder breathing reg. It is not they can not get enough air, but if you think you can't...


Bob

 

[WrmBluH2O]

...Sure, I've breathed on a buddy's reg and had to wonder how they can survive on such a crappy reg, but for the most part I simply breathe in, then out and repeat...

 

[WrmBluH2O]

Second stages perform pretty much the same regardless of depth, although there are some caveats. If you feel increased inhalation effort at depth, it's due to the increased workload on the first stage. In your case, if you had a very high quality first stage (like an atomic) and you really did experience increased WOB at 50-60 feet, it means something was wrong with either the 1st stage or the tank valve. Maybe a restriction in the filter or the tank valve was only partially open, could be any number of things.

More likely what you experienced was psychological, considering it was one of your first dives. But occasionally tank valves do get clogged or left mostly shut by well meaning DMs. That will definitely cause increased breathing effort at depth.

The reason 2nd stages function more-or-less the same at all depths is because the 1st stage compensates for depth by increasing the air pressure to the 2nd stage at the same rate ambient pressure increases at depth. Thus, 2nd stages always function with the same pressure gradiant. The caveat is that higher pressure air does have a slightly higher friction coefficient, but that's only noticeable at VERY deep depths, usually well beyond what anyone would breathe air. Helium blends for very deep diving lower the friction coefficient.

halocline,

Thank you for listing out the possible first stage and valve issues. I easily acknowledge that the issue is most likely psychological. But, I have had a few instances in life where I had made the assumption that "it's me" and then it surprisingly turned out to be the gear (relatively high end gear, no less).

Thanks, and happy diving!

 

[Nemrod]

The adjustment knobs are not really flow volume adjusters. They preload the spring on the second stage poppet to increase (or decrease) cracking force. Such adjustments can be useful to fine tune a regulator that is (purposely) over tuned and as well to offset swimming into a current.

My favorite regulators do not have the adjustment knobs. Titan LX Supreme, Conshelf. My 109 does, my wife's Legend does, I can take them or leave them.

N